Electrochemical-based sensors (e.g. self-monitoring blood glucose strips) are used for measuring analyte in fluid samples (e.g. whole blood). However, their accuracy can suffer from diffusion interfering factors (DIF) which affect analyte mass transfer in the test fluids, e.g. blood haematocrit (Hct) because red blood cells block the diffusion pathway of the analyte (e.g. glucose). Another factor negatively impacting the sensor accuracy is redox interfering factors (RIF) which result from any redox-active substance(s) that undergoes redox reactions and hence, generates interfering signals (e.g. uric acid interferes with electrochemical glucose measurement).
Technologies mitigating DIF are known. These use an active approach which relies on obtaining DIF sensitive signals, which are used to correct/compensate DIF. Examples of active DIF mitigation are described in US2002125145A1, US20090184004A1 and U.S. Pat. No. 8,016,997B2. These methods for DIF mitigation rely on determining diffusion between the two electrodes across the strip sample chambers. Hence, they can suffer from strip-to-strip variations in the sample chamber height.
Technologies mitigating RIF are known. Again, these use an active approach relying on obtaining RIF sensitive signals, which are for correction/compensation. Examples of active RIF mitigation for self-monitoring blood glucose are described in US2002125145A1 and WO2014037745A1.
The above mentioned technologies address only DIF or RIF, or separately address DIF and RIF using different techniques/methods.
Mitigation of both DIF and RIF to meet product accuracy requirements is essential. There is a need for improved techniques for achieving this mitigation.